does the turbo coolant circulate after turning engine off on 2012 bmw 640i

What is your question?

I see that the 2012 BMW 640i has an aux.water coolant pump for the turbo charger, I assume that is for keeping the turbo bearings cool, so does it continue to circulate the water after you turn off the engine. Also should I be concerned about the condition of the turbo if I purchase this 2012 BMW 6401 with 51,000 miles on it Thanks Geoff

What makes this problem better or worse?

no known problems

How long has your 2012 BMW 640i had this problem?

none considering purchasing